This is an original prospective randomized controlled study focused on the preoperative use of this drug in patients with impaired left ventricular function which is associated with a high operative risk (i.e. EuroSCORE). Perioperative myocardial stunning is particularly evident in this cohort of patients. Prophylactic administration of levosimendan the day before the operation could be translated in improved myocardial performance intraoperatively and during the early postoperative period.